JP2006179928A - Sensor assembly, digital serial bus and protocol, sensor network, and lithography device and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and a method that transfer data in a lithography device. <P>SOLUTION: A sensor assembly as an embodiment includes a sensor, an analog-digital converter which is configured to digitize a data signal received from the sensor, and an array of logic elements configured to receive data of 1st data transfer on a serial bus and transfer data of 2nd data transfer including information in the signal digitized on the serial bus. The array of logic elements transfers data of the 2nd data transfer according to information received by the 1st data transfer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a system and method for transferring data within a lithographic device.

  A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such cases, a patterning device, alternatively referred to as a mask or reticle, can be used to generate a circuit pattern corresponding to an individual layer of the IC. This pattern can be transferred onto a target portion (eg including part of, one, or more dies) on a substrate (eg a silicon wafer). The transfer of the pattern is usually via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate.

  In general, a single substrate will contain a network of adjacent target portions that are successively irradiated. A known lithographic apparatus scans a pattern with a projection beam in a predetermined direction ("scanning" direction), a so-called stepper, in which each target portion is irradiated by exposing the entire pattern once to the target portion, and A so-called scanner is also included in which each target portion is irradiated by simultaneously scanning the substrate in parallel or antiparallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

  The lithographic apparatus may include a number of sensors for monitoring conditions within the apparatus, such as local temperature and received light. The sensor is typically coupled to an electronic rack outside the device, the rack including one or more cards inserted into one or more backplanes. Lithographic devices typically use analog signal paths to couple sensors to an electronic rack.

  As extreme ultraviolet (EUV) lithography has developed, problems have arisen regarding the vacuum environment in which EUV exposure is performed. In vacuum, the cable causes gas evolution, which causes vacuum contamination and potentially leads to contamination of the optical elements. Another problem with operating electronics in a vacuum is the absence of an atmosphere that conducts conduction heat, which complicates the use of circuit elements that generate heat.

  Within the sensor bus, reliability and support for real-time work may also be desirable.

  A sensor assembly according to one embodiment includes a sensor configured to output sensor data, an analog-to-digital converter configured to receive an analog signal corresponding to the sensor data and output a digital signal of the sensor data including. The sensor assembly further includes a local processor configured to receive a first data transfer on the digital serial bus from the remote processor and transfer a second data transfer on the digital serial bus. The local processor can be configured to transfer the second data transfer based on the information received in the first data transfer.

  According to another embodiment, a method for providing data to a remote processor includes receiving information on a serial data line from a remote processor, generating an analog signal corresponding to a condition sensed at a measurement site, and local to the measurement site. Acquiring a digital signal based on an analog signal at a typical location, outputting a serial data stream based on a digital signal on a serial data line at a location local to the measurement site, and information on the serial data line Including communicating. At least one of generating an analog signal, acquiring a digital signal, and outputting a serial data stream is performed according to pre-trigger information received on the serial data line.

  A method of data acquisition according to a further embodiment includes transferring digital control information over a serial data bus to a sensor assembly in a vacuum zone, where the digital control information includes an address of the sensor unit. The method includes receiving a serial data stream on a serial data bus according to the control information, the serial data stream including digital sensor data from a sensor assembly.

  Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings. Corresponding reference symbols indicate corresponding parts in the drawings.

  Embodiments of the present invention can be applied to provide a digital bus to an optical sensor of a lithography machine.

  FIG. 1 schematically depicts a lithographic apparatus according to one embodiment of the invention. The apparatus is constructed to support an illumination system (illuminator) IL configured to condition a radiation beam B (eg UV radiation, EUV radiation or other radiation) and a patterning device (eg mask) MA. And a support structure (for example, a mask table) MT connected to a first positioning apparatus PM configured to accurately position the patterning device according to specific parameters, and a substrate (for example, a resist-coated wafer) W. A substrate table (e.g. wafer table) WT coupled to a second positioning device PW constructed to support and configured to accurately position the substrate according to specific parameters, and radiation by a patterning device MA The pattern imparted to the beam B is changed to a target portion C (eg If, and one or more a projection system configured to project the composed of the die) of (e.g. refractive projection lens system) PS.

  The illumination system includes various types of optical components, such as refraction, reflection, magnetic, electromagnetic, electrostatic, or other types of optical components, or combinations thereof, for directing, shaping, or controlling radiation. be able to.

  The support structure supports, ie bears the weight of, the patterning device. This holds the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions, such as for example whether or not the patterning device is held in a vacuum environment. The support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure may be a frame or a table, for example, which may be fixed or movable as required. The support structure may ensure that the patterning device is at a desired position, for example with respect to the projection system. Any use of the terms “reticle” or “mask” herein may be considered synonymous with the more general term “patterning device”.

  As used herein, the term “patterning device” should be broadly interpreted as referring to a device that can be used to provide a pattern in a cross section of a radiation beam so as to produce a pattern in a target portion of a substrate. It is. It should be noted that the pattern imparted to the radiation beam may not exactly correspond to the desired pattern at the target portion of the substrate, for example if the pattern includes phase shifting features or so-called assist features. In general, the pattern imparted to the radiation beam corresponds to a special functional layer in a device being created in the target portion, such as an integrated circuit.

  The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include not only various hybrid mask types but also mask types such as binary masks, Levenson masks, attenuated phase shift masks. One example of a programmable mirror array uses a matrix array of small mirrors. Each of the mirrors can be individually tilted to reflect an incident radiation beam in a different direction. The tilted mirror imparts a pattern to the radiation beam reflected by the mirror matrix.

  As used herein, the term “projection system” refers to, for example, refractive optics used, catadioptric systems, catadioptric systems, as appropriate to other factors such as the exposure radiation used, or the use of immersion fluids or the use of vacuum. It should be construed broadly to cover various types of projection systems, including optical systems, magneto-optical systems, electromagnetic optical systems, and electrostatic optical systems. Any use of the term “projection lens” herein may be considered as synonymous with the more general term “projection system”.

  As shown here, the apparatus is of a transmissive type (eg using a transmissive mask). Alternatively, the device may be of a reflective type (eg using a programmable mirror array or using a reflective mask).

  The lithographic apparatus is of a type having two (dual stage) or more substrate tables (and / or two or more mask tables). In such “multi-stage” machines, additional tables are used in parallel. Alternatively, the preliminary process is performed on one or more tables while one or more other tables are used for exposure.

  The lithographic apparatus may be of a type wherein at least a portion of the substrate is covered with a liquid having a relatively high refractive index, such as water, so as to fill a space between the projection system and the substrate. An immersion liquid may be applied to other spaces in the lithographic apparatus, for example, between the mask and the projection system. Immersion techniques are well known for increasing the numerical aperture of projection systems. As used herein, the term “immersion” does not mean that a structure, such as a substrate, must be immersed in liquid, but merely means that liquid is placed between the projection system and the substrate during exposure.

  Referring to FIG. 1, the illuminator IL receives a radiation beam from a radiation source SO. The source and the lithographic apparatus may be separate entities, for example when the source is an excimer laser. In such a case, the source is not considered to form part of the lithographic apparatus, and the radiation beam is emitted from the source SO to the illuminator with the aid of a beam delivery system BD including, for example, a suitable collector mirror and / or beam expander. Passed to IL. In other cases, for example when the source is a mercury lamp, the source may be an integral part of the device. The source SO and the illuminator IL can be referred to as a radiation system together with the beam delivery system BD as required.

  The illuminator IL may include an adjuster AD configured to adjust the angular intensity distribution of the radiation beam. In general, the external and / or internal radiation range (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution at the pupil plane of the illuminator can be adjusted. The illumination device IL also includes various other components such as an integrator IN and a capacitor CO. The illuminator can be used to adjust the radiation beam so that it has the desired uniformity and intensity distribution across its cross section.

  The radiation beam B is incident on the patterning device (eg, mask MA), which is held on the support structure (eg, mask table MT), and is patterned by the patterning device. The radiation beam B passes through the mask MA and passes through a projection system PS that focuses the beam onto a target portion C of the substrate W. With the help of the second positioning device PW and the position sensor IF (for example an interferometer device, linear encoder or capacitive sensor), the substrate table WT can be accurately aligned, for example to align with different target portions C in the path of the radiation beam B Can exercise. Similarly, using the first positioning device PM and another position sensor (not explicitly shown in FIG. 1), for example after mechanical retrieval from a mask library or during a scanning movement, the radiation beam The mask MA can be accurately positioned with respect to the path B.

  In general, the movement of the mask table MT is performed by a long stroke module (coarse positioning) and a short stroke module (fine positioning) that form part of the first positioning device PM. Similarly, movement of the substrate table WT can be realized using a long stroke module and a short stroke module forming part of the second positioning device PW. In the case of a stepper (as opposed to a scanner) the mask table MT is only connected to a short stroke actuator or is fixed. Mask MA and substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. The substrate alignment mark as shown occupies a dedicated target position, but may be arranged in a space between target portions (referred to as a scribe lane alignment mark). Similarly, in situations where a plurality of dies are provided on the mask MA, mask alignment marks may be placed between the dies.

The device represented here can be used in at least one of the following modes:
1. In the step mode, the mask table MT and the substrate table WT are basically kept stationary. Then, the entire pattern given to the radiation beam is projected onto the target portion C at one time (that is, one static exposure). The substrate table WT can then be shifted in the X and / or Y direction and a different target portion C can be irradiated. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.
2. In the scanning mode, the mask table MT and the substrate table WT are scanned synchronously, while the pattern given to the radiation beam is projected onto the target portion C (that is, one dynamic exposure). The speed and direction of the substrate table WT relative to the mask table MT is determined by the enlargement (reduction) and image reversal characteristics of the projection system PL. In scan mode, the maximum size of the exposure field limits the width of the target portion (in the non-scan direction) with a single dynamic exposure, and the length of the scanning operation determines the height of the target portion (in the scan direction). To do.
3. In another mode, whether the substrate table WT operates while the mask table MT is essentially kept stationary to hold the programmable patterning device and project the pattern imparted to the radiation beam onto the target portion C. Scanned. In this mode, a pulsed radiation source is typically used to update the programmable patterning device as needed each time the substrate table WT is operated or between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as referred to above.

  Combinations and / or variations on the above described modes of use or entirely different modes of use may also be employed.

  In one embodiment of the invention, the lithographic apparatus may include a number of sensors to monitor conditions such as local temperature and received light among other conditions. In one example, an energy sensor is used to indicate the energy of the illumination beam. Such a sensor can be realized with a light emitting diode positioned behind the mirror in the beam path (eg, between the radiation source and the reticle). The mirror can be made of aluminum and can be the reflective surface of a prism, and is usually designed to transmit only a small portion (eg, 1 percent) of beam energy to the sensor. A lens and filter may be placed in the path between the mirror and the energy sensor. In one embodiment, Peltier elements and temperature sensors can be used to keep the temperature of the energy sensor constant.

  A spot sensor can be used to measure the light intensity of the illumination field at the wafer stage level. Measurements acquired by spot sensors (which may be realized using light emitting diodes) can be used for dose control.

  A quad cell can be used to measure reticle, light source and / or wafer alignment. To pre-align the reticle, one or more quad cells are mounted on the reticle table and illuminated (eg, with LEDs) to determine the alignment of the reticle relative to the table. In the relative alignment of the reticle and wafer, an image of the wafer mark is projected onto the reticle mark while moving at least one of the reticle and wafer relative to the other, and as a result, the light emitted from the reticle mark is projected by the quad cell. Perceived.

  In one embodiment, the quad cell includes four photosensitive elements (eg, photodiodes or photoelectric cells). Usually, one electrode is common to each element. Each quadrant of the quad cell generates a current that is proportional to the intensity of the illumination hitting it. A transconductance amplifier can be used to convert the current into a transfer and a filter can be used to remove noise (eg, from mechanical resonance) from the signal.

  FIG. 2 shows an example of the analog architecture of the sensor network 100. In this example, the network includes one or more sensors 120, such as photosensitive sensors, temperature sensitive sensors, pressure sensitive sensors, magnetic sensitive sensors, charge sensitive elements and / or other sensors. These sensors may be active or passive and include one or more semiconductor elements. In one example, the network 100 may include a sensor 120 having a photosensitive semiconductor PN junction (eg, a photodiode or phototransistor).

  Each sensor 120 may be coupled to a corresponding analog circuit 130, such as one or more amplifiers, filters, impedance matching elements, vice power supplies, or other components. A signal output from the sensor 120 or the circuit 130 can be conveyed to the signal processing unit 150 on the corresponding analog signal line 140. Each analog signal line 140 can be realized as a long line. The signal processing unit 150 may be mounted in an electronics rack or included in a relatively large system mounted in such a rack that is located away from the sensors. The signal processing unit 150 includes one or more analog-to-digital converters (ADC) 160, each receiving a signal on a corresponding analog input line 140.

  The analog signal received from sensor 120 or circuit 130 and converted to a digital signal by ADC 160 can then be processed, stored and / or transferred (eg, to another processor) by processor 170. The processor 170 may be implemented as one or more microprocessors, DSP units, FPGAs or similar programmable devices, or other arrayed logic elements. In one application, the processor 170 can be implemented as an embedded microcontroller. The signal processing unit 150 can output, for example, a control signal for controlling multiplexing of analog signals to the analog signal line 140.

  A sensor network having an analog architecture can be limited in terms of signal-to-noise ratio (SNR) and dynamic range of measurements as received by the signal processing unit 150. Such networks also have other drawbacks in certain environments. For example, in high vacuum applications, among other problems, it is desirable to minimize the overall length of the sensor signal line in vacuum due to cable insulation outgassing from the analog signal line 140. Therefore, the length of the standard analog signal line 140 cannot be used conveniently in a high vacuum environment. One exemplary environment is an exposure area of a machine in EUV lithography, where sensors can be deployed to measure parameters such as temperature, dose, intensity, etc. Transferred to the outer processing unit.

  FIG. 3 illustrates an example digital architecture of a sensor network 200 according to an embodiment of the present invention. Each sensor assembly 210 may include at least one sensor 220, such as a photosensitive sensor, a temperature sensitive sensor, a pressure sensitive sensor, a magnetic sensitive sensor, a charge sensitive element, and / or other sensors. The sensor may be active or passive and includes one or more semiconductor elements. The sensor 220 may be the same as the sensor 120 used in the analog network 110, or may be different, for example, to accommodate particular embodiments of other elements of the sensor assembly 210. The sensor can be configured to measure pressure, acceleration, object presence, and other measurements.

  In one embodiment, the network 200 may include one or more sensors 220 having a photosensitive semiconductor PN junction that includes a photodiode or phototransistor. Although FIG. 3 shows two sensor assemblies 210, the network 200 may include any number of such assemblies, and the assemblies may include different types of sensors 220 in some cases. Sensor assembly 210 may be coupled to digital serial bus 240. In an alternative embodiment, sensor assembly 210 can be coupled to multiple digital serial buses.

  Each sensor assembly 210 may also include an analog circuit 230 such as one or more amplifiers, filters, impedance matching elements, vice power supplies, or other components. In one embodiment of the invention, the analog circuit 230 may be the same as the circuit 130 used in the analog network 100. In an alternative embodiment of the present invention, the analog circuit 230 may include sensors such as noise susceptibility, interference and / or temperature, among other conditions, and / or environmental specific constraints such as the risk of contamination, among other constraints. It may be different from circuit 130 to suit a particular embodiment of other elements of assembly 210.

  Each sensor assembly 210 may also include an ADC 260 that converts the analog signal from the corresponding analog circuit 230 into a digital signal, and a local processor 270 that receives the digital signal from the ADC 260. The local processor 270 may be implemented as a microprocessor, microcontroller, DSP unit, EPGA or other programmable device, or another array of logic elements. The local processor 270 can be realized as a semiconductor memory such as SRAM, DRAM, or FLASH among other memories, and may include a storage device that can be mounted on the same chip as the local processor 270 in some cases. Such a storage device can be used to store information such as measurement data, configuration data and / or other working parameters based on, for example, packets received on the digital serial bus 240.

  In one embodiment of the present invention, converter 280 may be a serial-to-parallel converter that receives a digital signal from a local processor in serial form, converts the signal to serial form, and transfers the signal over digital serial bus 240. . In another embodiment of the invention, the signal may be an electrical signal having a potential that varies with time relative to a reference potential. In alternative embodiments, the serial-to-parallel converter can be configured to transfer digital signals over a wireless, optical, fiber optic or other communication medium.

  In one embodiment of the invention, serial to parallel converter 280 may receive a signal (eg, a packet) from digital signal bus 240, convert the signal to parallel form, and transfer the signal to local processor 270. it can. In yet another embodiment, a serial to parallel converter 280 is configured using a universal asynchronous receiver transmitter (UART) that includes one or more buffers and / or other elements as is known in the art. Can be implemented. In some embodiments of sensor assembly 210, local processor 270 and transducer 280 can be integrated into the same array of logic elements. Within sensor assembly 210, one or more of ADC 260, local processor 270, and transducer 280 may be implemented on the same chip or in the same chip package. Other configurations may be used.

  FIG. 4 shows a signal processing unit 250 that can be connected to the digital serial bus 240. The signal processing unit 250 can control the sensor assembly 210 to process data measured by the sensor assembly 210. The processor 275 can be implemented as a microprocessor, microcontroller, DSP unit, FPGA or other programmable device, or another array of logic elements. The processor 275 communicates with memory such as semiconductor RAM or other memory, storage devices such as hard disks or other storage devices, or other devices on a network such as wired, wireless, optical and / or other networks. Can do. In addition to communicating with sensor assembly 210, processor 275 performs other tasks such as processing data and / or controlling other systems, communicates with other devices on digital serial bus 240, or the like. Both can be performed.

  The elements of the signal processing unit 250 can be mounted together in a rack, but these elements need not be in the same enclosure or on the same card. In one embodiment of the present invention, the signal processing unit 250 can be positioned at a distance from at least some of the sensors that are located away from the sensed environment. For example, in a vacuum environment, it may be desirable to place unit 250 outside the vacuum zone. In another embodiment of the present invention, the network 200 can include sensors or sensor assemblies local to the signal processing unit 250 to monitor ambient temperature or other control conditions for the environment being sensed.

  By placing an intelligent ADC, such as an ADC and digital processing logic, in each sensor, the signal may be digitized as close as possible to the measurement location. In alternative embodiments, more than one ADC may be placed on each sensor. Such proximity of transforms allows for higher dynamic range and SNR. For digital interface designs, it is desirable to allow a flexible number of sensor assemblies 210 to be coupled to a single bus 240 through multidrop cables or other coupling devices.

  In an exemplary embodiment, two or more ADCs can be configured to operate in parallel to enhance processing. For example, the sensor 220 can perform a first measurement (eg, a darkness measurement) immediately before the lithographic apparatus generates a light pulse, and can perform a second measurement immediately after the lithographic apparatus generates a light pulse. The ADC 260 may be configured to subtract the first measurement value from the second measurement value. If the amount of time that elapses between the first measurement and the second measurement is less than the conversion time of one ADC 260, use two or more ADCs 260 in an alternative way to avoid measurement loss Can do.

  Due to vacuum constraints, such as no air carrying conducted heat, allowable power losses in the vacuum area of the components such as sensor assembly 210 and local processor 270 can be limited. Low power operation has advantages in other situations. For example, in applications where dimensional variations should be avoided, it is desirable to minimize local heating. Thus, low power operation of the sensor assembly 210 is advantageous in lithography even at atmospheric pressure to minimize local heating, such as at a spot sensor or other location on the wafer stage of the lithographic apparatus.

  Setting a limit on power loss may also limit the maximum allowable baud rate. This is because as the baud rate increases, the switching frequency usually increases and the power loss increases. The reduction in baud rate limits the number of sensor values transmitted between two adjacent sensing events (e.g., laser pulses used to expose patterns such as circuit designs on the photosensitive substrate) via the digital serial bus 240. can do. In this embodiment, a special low-electricity electronic device can be used to support a baud rate of up to 2.4 Mbit / sec. In alternative embodiments, higher or lower baud rates can be used.

  In one embodiment of the invention, time slots can be used to maximize baud rate. The time slot can be defined based on the time period expected to receive data from the selected sensor assembly 210. In one embodiment, a time slot may be defined based on a cycle and may include the passage of time within the cycle. In the exemplary embodiment, the time slot is a cycle in which the slave device 504 can perform operations such as triggering and / or measurement, a cycle in which the slave device 504 can respond, a delay in which the slave device 504 can respond during the cycle, And other timing information. Examples of time slots are described in more detail with respect to FIG.

  In further embodiments of the present invention, the sensor assembly 210 may be provided with prior notification as to when to perform measurements and when to provide measurements to the processor 275 or other receiving device. Such pre-scheduling of data transfer can facilitate real-time operation of the network 200 and reduce overhead such as may result from access negotiations and / or data collisions.

  The potential advantages of implementing the digital network 200 compared to the analog network 100 are, among other things, the overall cable length that allows for improved dynamic range and / or signal-to-noise ratio measurements and corresponding gas emission level reduction in a vacuum environment. And reducing power consumption by enabling component hibernation. Digital configurations can also improve flexibility compared to analog solutions. For example, operational parameters of sensor assembly 210, such as sensor configuration, such as measurement range, selection from multiple local sensors and / or timing of measurements, can be changed using software. Also, in some embodiments, sensed data can be processed within sensor assembly 210, thereby potentially reducing the amount of data to be transmitted on bus 240. An additional advantage of processing data within the sensor assembly is that multiple measurements can be integrated. The present invention also provides other advantages.

  In one embodiment of the invention, the sensor assembly 210 can correspond to a slave device and the associated remote processing unit 250 can correspond to a master device. In alternative embodiments of the present invention, multiple master devices can be associated with multiple slave devices, and one or more master devices can actively communicate with multiple slave devices. In a configuration that allows for one “active” master, an “active” master can be dynamically assigned from among multiple master devices.

  In order to minimize power loss due to the sensor assembly 210, it is desirable to reduce the number of bits transmitted between the slave device and the master device. When performing communication over the digital serial bus 240, it is desirable to use a protocol that is optimized for low overhead. A suitable half-duplex bus for real-time data acquisition will now be described. Other configurations such as a full duplex bus may also be used.

  In one embodiment of the present invention, a 12-bit packet containing address bits can be used to reduce address packet overhead. The address bits can also allow power savings by allowing the slave to sleep until it is accessed. In another embodiment of the present invention, this real-time sensor bus protocol is implemented to provide a low power and reliable multi-drop serial bus that communicates with a digital sensor within the vacuum environment of one or more EUV machines. Can do. In alternative embodiments, the real-time sensor bus protocol can be applied to other sensing applications.

  FIG. 5 shows a context diagram of a digital network 200 that can be implemented using a protocol according to one embodiment of the invention. In this example, master device 502 can communicate with slave devices corresponding to up to 25 sensor assemblies 210 corresponding to signal processing unit 250. Other configurations or numbers of devices may be used.

  The real-time sensor bus protocol can be built in a frame that includes addresses, data blocks, and additional information bytes, especially length and checksum. With this protocol developed by the OSI model, the master device 502 can control all data traffic using the digital serial bus 240.

  In one embodiment of the present invention, two types of communication modes can be realized. That is, one-to-one mode (master / slave / master) and broadcast mode (master / slave / master). For the two types of communication modes, four types of frames can be generated including a one-to-one master frame, a one-to-one slave frame, a broadcast master frame, and a broadcast slave frame.

  FIG. 6 shows an example of a data frame transmitted in a one-to-one mode for a corresponding one-to-one master frame and a corresponding one-to-one slave frame. In one embodiment of the invention, the one-to-one master frame may include one address byte 602, a length byte 604, one or more data bytes 606 (606 a-606 n), and a checksum byte 608. Address byte 602 contains the address of the slave selected to receive the information. In another embodiment of the invention, the one-to-one slave frame may include a length byte 612, a one-to-one data byte 614 (614a-614n), and a checksum byte 616.

  The one-to-one mode is a direct method for the master device 502 to communicate with the slave device 504. In one embodiment of the present invention, the master device 502 can send a one-to-one master frame to all slave devices 504 that include a request or instruction for the selected slave device 504. Optionally, the one-to-one master frame can include data for the selected slave device 504. Slave devices 504 that are not selected to receive the one-to-one master frame are configured to ignore the frame. In an exemplary embodiment, a one-to-one instruction can be used during the initialization phase to set up the digital serial bus 240 and slave devices.

  In another embodiment, the selected slave device 504 is configured to respond to a one-to-one slave frame, and thus to respond to instructions from the master device 502, optionally with data requested from the master device 504. Can be included. The selected slave device 504 provides configuration data including microcontroller temperature, random number, software version identification, all previous data, test output, sensor firmware upload, and other configuration data at the slave device. be able to. Alternatively, the selected slave device 504 can provide data measured by the selected slave device 504 for a state remote from the slave device 504. Unselected slave devices 504 can be configured to ignore the one-to-one slave frame transmitted by the selected slave device 504.

  FIG. 7 shows an example of a data frame transmitted in broadcast mode for a corresponding broadcast master frame and a corresponding broadcast slave frame. In one embodiment of the invention, the broadcast master frame can include one address byte 702. A broadcast slave frame may include one, two, or four data bytes as determined by the master device 502. In one embodiment of the invention, the broadcast mode can be implemented during system operation.

  In the broadcast mode, the master device 502 can transmit one broadcast master frame to all slave devices 504 simultaneously. In one embodiment of the invention, slave device 504 may be configured not to acknowledge receipt of a broadcast master frame. In another embodiment, the selected slave device 504 can respond to the master device 502 with a corresponding prescribed time interval broadcast slave frame set by the master device 502, and thus in real time. Can be operated. Before sending the broadcast command, the master device 502 may respond to all slave devices 504 in which cycle the slave device 504 performs operations such as triggering and / or measurement, and in which cycle the slave device 504 responds. Timing information can be provided, such as at what time in the cycle the slave device 504 may reply and other timing information. The timing information is hereinafter referred to as a time slot. Time slots can be provided to slave devices 504 through a one-to-one master frame.

  The master device 502 can also provide information to the slave device 504, such as how many data packets can be used to respond. For example, the selected slave device 504 is instructed to send a response in one, two, or four packets, respectively. In other embodiments, the selected slave device 504 may respond with three packets, the selected slave device 504 may be acceptable with more than four packets, or both.

  FIG. 8 shows the contents of a packet that can be used to construct a frame according to one embodiment of the serial protocol. The packet includes two framing bits (start bit 802 and stop bit 814), error detection bit 812 (parity), status bit 810 (indicates whether the data field has data or address), and an 8-bit data field 804- 808 may be included.

  FIG. 9 illustrates an exemplary embodiment of broadcast mode data transmission. In this example, master device 502 can initialize all slave devices 504 so that slave device 504 responds differently to various broadcast master frames. In one embodiment of the present invention, the broadcast master frame identifies the number of cycles that the slave device 504 can perform operations such as measuring data, waiting for a response, not performing any operation, among others. Information is provided to slave device 504. Also, in order to prevent multiple slave devices 504 from responding simultaneously, the slave device 504 uses a response delay as a start indicator and forwards a broadcast slave frame.

  Referring to FIG. 9, the configuration of sensors on the digital serial bus is illustrated. The trigger cycle, response cycle, response delay, and response length settings are shown for each slave device. Prior to sending any broadcast master frame, the master device 502 provides the selected slave device 504 with a pre-trigger instruction including trigger cycle, response cycle, response delay, and response length, address, among other parameters. can do. In one embodiment, eight addresses are reserved and used for pre-trigger instructions, each address corresponding to a cycle. Thus, eight cycles can be defined by the master device 502. If one or more of these parameters are not set on the slave device 504 prior to receiving the broadcast master frame, the slave device that does not have the complete set of parameters responds to the broadcast message. I can't.

  In the exemplary embodiment, master slave 502 can transmit multiple broadcast master frames and cycle numbers at a predefined frequency. This frequency may correspond to the frequency at which a light source such as a laser or EUV source is triggered to emit light. As shown in FIG. 9, the master device 502 can transmit four different broadcast master frames, 1 to 4 cycles, at a frequency of 10 kHz.

  The slave device 504a corresponding to sensor 1 can be initialized to perform measurement in cycle 2 and transfer measurement data in two packets after delay B in cycle 2. The slave device 504b corresponding to the sensor 7 performs the measurement at cycle 0 (that is, at each cycle), and initializes the measurement data to be transferred in two packets after delay A at cycle 0 (each cycle). Can do. Quad cell 902 includes four slave devices to measure reticle, light source and / or wafer alignment during cycle 1 and 2 after the corresponding delay C or D during corresponding cycles 1-4. Measurement data can be transferred in one packet.

  Advantages of embodiments of the present invention include, among other things, reduced cable length, reduced power consumption, and real-time operation. While embodiments of the present invention are suitable for use in a vacuum environment, these and other embodiments can be used in other conditions, such as atmospheric or other pressures. For example, such an architecture may be deployed in an atmospheric pressure lithography environment. Such a network configuration can also be used for sensors other than those explicitly described, such as temperature sensors or other sensors.

  Although particular reference is made herein to the use of lithographic apparatus in the manufacture of ICs, it should be clearly understood that the lithographic apparatus described herein can also be used in many other applications. For example, it can be used in the manufacture of integrated optical devices, magnetic domain memory guidance and detection patterns, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads and the like. In these alternative application contexts, the terms “wafer” or “die” as used herein may be used interchangeably with more general terms such as “substrate” or “target portion”, respectively. It will be understood by those skilled in the art. The substrate referred to herein can be processed before or after exposure, for example, with a track (usually a tool that applies a layer of resist to the substrate and develops the exposed resist) or a metrology or inspection tool. Where appropriate, the disclosure herein may be applied to these and other substrate processing tools. In addition, the substrate can be processed multiple times, for example to produce a multi-layer IC, so the term substrate as used herein also refers to a substrate that already contains multiple processed layers.

  Although the foregoing specifically refers to the use of embodiments of the present invention in the context of optical lithography, the present invention can also be used in other applications such as stamped lithography and is not limited to optical lithography, if the situation allows. I understand that. In imprint lithography, the structure of the patterning device defines the pattern that is produced on the substrate. The patterning device structure is pressed against a layer of resist supplied to the substrate, after which electromagnetic radiation, heat, pressure, or a combination thereof is applied to cure the resist. The patterning device is moved away from the resist, leaving a pattern after the resist is cured.

  As used herein, the terms “radiation” and “beam” include not only particle beams such as ion beams or electron beams, but also ultraviolet (UV) radiation (eg, wavelengths of 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm). ) And extreme ultraviolet (EUV) radiation (eg having a wavelength in the range of 5 nm to 20 nm) is used to cover all types of electromagnetic radiation.

  The term “lens” refers to any of a variety of types of optical components, or combinations thereof, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components, as the situation allows.

  While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, the present invention provides a computer program that includes one or more sequences of machine-readable instructions that describe a method as disclosed above, or a data storage medium (eg, semiconductor memory, having such a computer program within itself). Magnetic or optical disk).

  The foregoing presentation of the described embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments are possible, and the general principles presented herein can be applied to other embodiments. For example, the present invention may be implemented in part or in whole as a wired circuit, as a circuit configuration that creates an application specific integrated circuit, or from a data storage medium as a firmware program or machine readable code loaded into a non-volatile storage device, or Such code can be implemented as a software program loaded into a data storage medium, such instructions being executable by an array of logic elements such as a microprocessor or other digital signal processing unit. It is intended that the specification be considered as exemplary only and, therefore, the scope of the invention be limited only by the claims.

1 depicts a lithographic apparatus according to an embodiment of the invention. An analog sensor network 100 is shown. 1 illustrates a sensor network 200 according to an embodiment of the present invention. Another part of the sensor network 200 is shown. 1 is a context diagram of a digital network according to an embodiment of the present invention. An example of data transferred in the one-to-one mode is shown. An example of data transferred in the report mode is shown. Fig. 5 shows the contents of a packet matching a protocol according to an embodiment of the present invention. It shows another example of data transferred in the report mode.

Claims (31)

A sensor assembly,
A sensor configured to output sensor data;
An analog-to-digital converter configured to receive an analog signal corresponding to the sensor data and output a digital signal of the sensor data;
A local processor electrically coupled to the analog-to-digital converter and configured to receive a first data transfer from a remote processor and transfer a second data transfer;
A sensor assembly, wherein the local processor is configured to transfer the second data transfer based on information received in the first data transfer.   The sensor assembly of claim 1, wherein the first data transfer includes a pre-trigger instruction and the second data transfer includes an acknowledgment of receipt of the pre-trigger instruction.   The sensor assembly of claim 2, wherein the first and second data transfers include data frames, and the first data byte of the first data transfer includes an address of the target sensor assembly.   The sensor assembly of claim 1, wherein the first data transfer includes an address packet and the second data transfer includes sensor data.   The sensor assembly of claim 1, wherein the sensor data includes one of measurement data and configuration data.   The sensor assembly of claim 1, wherein the second data transfer is initiated based on information received in the first data transfer.   3. The sensor assembly of claim 2, wherein the local processor transfers the second data transfer based on a time slot defined by the first data transfer pre-trigger instruction.   The sensor assembly of claim 1, wherein the local processor is coupled to the bus.   The sensor assembly of claim 8, wherein the bus is a digital serial bus.   The sensor assembly according to claim 2, wherein the digital signal includes information corresponding to a value of the sensor data measured at a time indicated by the pre-trigger instruction of the first data transfer. The sensor assembly includes a plurality of sensors;
The digital signal includes information corresponding to the value of the sensor data received from the selected sensor;
The sensor assembly of claim 4, wherein the selected sensor is selected based on information received in a first data transfer.   The sensor assembly of claim 1, wherein the sensor has a photosensitive element.   The sensor assembly of claim 1, wherein the sensor assembly is configured to operate in a vacuum. A method for providing data to a remote processor, comprising:
Receiving information on a serial data line from a remote processor;
Generating an analog signal corresponding to the state sensed at the measurement site;
Acquiring a digital signal based on an analog signal at a location local to the measurement site;
Outputting a serial data stream based on a digital signal on a serial data line at a location local to the measurement site;
Communicating information to a remote processor over a serial data line;
A method wherein at least one of generating the analog signal, acquiring a digital signal, and outputting a serial data stream is performed in accordance with pre-trigger information received on the serial data line.   Receiving information on the serial data line includes receiving information as a first data frame, the serial data stream includes a second data frame, and the first data byte of the first data frame is transmitted to the target sensor assembly. The method of claim 14, comprising an address.   15. The method of claim 14, wherein receiving information on the serial data line includes receiving a pre-trigger instruction for a first data frame, and the serial data stream includes an acknowledgment of receipt of a pre-trigger instruction for a second data frame. the method of.   The method of claim 14, wherein outputting the serial data stream is initiated based on information received on the serial data line.   The method of claim 16, wherein outputting the serial data stream is based on a time slot defined by a pre-trigger instruction received on the serial data line.   The method of claim 16, wherein the digital signal includes information corresponding to a value of the measurement signal measured at a time indicated by the pre-trigger instruction received on the serial data line. The method includes generating a plurality of analog signals corresponding to conditions sensed at a measurement site;
The digital signal includes information corresponding to a value of a selected one of the plurality of analog signals;
The method of claim 14, wherein a selected one of the plurality of analog signals is selected based on the information received on a serial data line.   The data measurement method of claim 14, wherein generating the analog signal includes generating an analog signal based on at least one of measurements of illumination, temperature, pressure, acceleration, and object presence detection.   The data measurement method according to claim 14, wherein the measurement site is arranged in a vacuum chamber. A data acquisition method,
Transferring digital control information over a serial data bus to a sensor assembly in a vacuum zone, wherein the digital control information includes an address of a sensor unit;
Receiving a serial data stream on a serial data bus based on the control information, the serial data stream comprising digital sensor data from a sensor assembly. Transferring the digital control information includes transferring a first data frame including the digital control information having a pre-trigger instruction;
The serial data stream includes a second data frame including the digital sensor data;
24. The data acquisition method according to claim 23, wherein the first data byte of the first data frame includes an address of the sensor assembly.   24. The data acquisition method according to claim 23, wherein the transfer of the digital control information includes a first data frame having an address packet, and the serial data stream includes a second data frame having the digital sensor data.   The data acquisition method according to claim 23, wherein the sensor data includes one of measurement data and configuration data.   24. A data acquisition method according to claim 23, wherein the serial data stream is transferred at a time allocated by digital control information.   25. The data acquisition method of claim 24, wherein the serial data stream is transferred based on a time slot defined by a pre-trigger instruction.   25. The data acquisition method according to claim 24, wherein the serial data stream includes information corresponding to a value of sensor data measured at a time indicated by a pre-trigger instruction of the digital control information. The serial data stream includes digital sensor data from a selected one of a plurality of sensor assemblies;
The data acquisition method of claim 23, wherein a selected one of the plurality of sensor assemblies is selected based on the digital control information.   The data acquisition method according to claim 23, wherein the digital sensor data includes at least one of illumination, temperature, pressure, acceleration, and object presence detection.

Images